Long-length low-loss polarization-maintaining fibers

Long-length low-loss polarization-maintaining fibers are useful for coherent optical transmission systems, active transmission lines with optical nonlinear effects, and other long-length optical transmission systems, such as those for bidirectional optical transmission. Design, fabrication, and characteristics of highly birefringent polarization-maintaining fibers with long length and low loss, especially polarization-maintaining and absorption-reducing (PANDA) fibers, are reviewed and discussed in this paper. Application of the fibers is also discussed.